One type of easy-open bottles have a neck with exterior helical threads around the defined bottle opening, and a metal closure cap that cooperates with the threads and allows it to be twisted about a quarter turn relative to the bottle to remove it from and open the bottle. Bottles of this type offer the appeal and convenience of being opened without the need of using any conventional opener tool. Beer and carbonated water are common liquids marketed in bottles of this type.
Normally, with the bare-handed thumb, the adjacent index finger, and the fleshy web portion of the hand therebetween wrapped around the sides of the cap, sufficient opening forces can be generated by gripping tightly onto the cap and twisting it off the bottle. However, with soft or sensitive skin, a weak grip, or should the bottle cap or one's hands be wet, the sharp side edges of the cap can dig into, cut or otherwise inflict pain via one's skin, and/or the cap can slip relative to the gripping hand to defeat the intended easy opening appeal of the bottle. To overcome this situation, it is common and generally effective to layer a thin flexible wrap or layer, such as a cloth or perhaps even a paper towel or napkin, between the cap and hand for protecting the hand and reducing pain and/or slippage.
While a conventional bottle opener tool can be used to snap off the cap without twisting it, this defeats the convenience of the easy-open bottle and moreover requires one to go to a tool (if such is mounted permanently on a cooler wall or the like) or to carry or otherwise keep track of the opener tool (if such is portable but not carried).
Special problems arise when professional servers of drinks, such as bartenders, must open many easy-open twist-off cap bottles over a short period, while concurrently handling many other unrelated chores including taking cash payments and making change, or making and serving other drinks. Thus, keeping track of or carrying around a portable opener tool or protective wrap can be a challenge, while otherwise having both hands free; and having a towel and/or opener tool dangle from one's belt can yield a questionable less than professional impression.
Another problem a snap-off opener tool can create is the removed cap is typically unrestrained and can fall to the floor and end up under nearby furniture or the like.